CN103812451A - Normal-temperature output port microwave variable-temperature noise source - Google Patents
Normal-temperature output port microwave variable-temperature noise source Download PDFInfo
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- CN103812451A CN103812451A CN201410039962.8A CN201410039962A CN103812451A CN 103812451 A CN103812451 A CN 103812451A CN 201410039962 A CN201410039962 A CN 201410039962A CN 103812451 A CN103812451 A CN 103812451A
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Abstract
The invention provides a normal-temperature output port microwave variable-temperature noise source, and aims to provide a microwave noise source, wherein the physical temperature of an output port of the noise source is at normal temperature, the equivalent output noise temperature can vary from 50K to 200K, and the noise source can be used for measuring ultralow noise factors of a microwave ultralow noise amplifier provided with a normal-temperature input port. According to the technical scheme, the normal-temperature output port microwave variable-temperature noise source is formed through the following steps: a microwave load (5) of the noise source, a microwave thermal insulation transmission line (6) and a microwave coaxial output port (8) are respectively provided with temperature sensors (7), wherein the temperature sensors (7) are distributed for monitoring the physical temperature of a microwave closed circuit; a cold head fixedly connected to a mains haft of a refrigerator (1) and the temperature sensors arranged on the microwave thermal insulation transmission line (6) in an array are sealed inside a low-temperature dewar (4), the cold head (2) in the dewar (4) is connected with a monitoring control circuit (3) through a temperature monitoring control line, and the microwave thermal insulation transmission line (6) passes through the normal-temperature microwave coaxial output port (8) outside a vacuum cavity wall in the radial direction.
Description
Technical field
The present invention relates in a kind of electronic applications, for measuring the microwave alternating temperature noise source of microwave ultra-low noise amplifier noise factor, more particularly, the present invention relates to a kind of measurement and have the microwave noise source of the noise factor parameter of the microwave ultra-low noise amplifier of ultra-low noise performance.Can think, the present invention, except for the noise-factor measurement of microwave ultra-low noise amplifier, can also be used for the amplitude linearity degree performance test of the microwave receiver such as noise-factor measurement and microwave radiometer of other microwave circuits similarly with ultra-low noise performance.
Background technology
As everyone knows, noise is a kind of natural phenomena, is a kind of forms of motion of material.In electronic equipment and system, inevitably all have noise, in general, noise is harmful to, because the interference of noise even can be flooded useful signal.In the radio system such as radar, communication, the noise factor parameter of the microwave amplifier of radio-frequency front-end has reflected the size of electronic equipment and system noise value, determine the key performances such as the sensitivity of whole system, therefore, the Measurement accuracy of noise figure of amplifier has been seemed to particularly important.The measurement of noise figure of amplifier at present is mainly used the equipment such as noise source and noise testing receiver.While thering is the noise-figure performance lower than the ultra-low noise amplifier of 0.5dB noise factor (conversion be 35K for equivalent input noise temperature) performance for measurement, for guaranteeing higher accuracy of measurement, should preferentially select to have the noise source of the equivalent output noise temperature being close with measured piece equivalent input noise temperature magnitude by noise testing theory.At present, in industry, conventionally use solid-state noise source to measure, but its equivalent output noise temperature is in 1000K～10000K magnitude, is obviously not suitable for the Measurement accuracy of such ultra-low noise coefficient.
For solving the measurement problem of this ultra-low noise coefficient, the low temperature noise source of useful liquid nitrogen cooling and the noise source system that normal temperature noise source is set up are also studied by indivedual research institution both at home and abroad, and its equivalent output noise temperature is respectively 80K left and right and 290K left and right.Wherein, the 6th phase " telecom technology " in 2005, a kind of low noise test and noise source automated calibration system automatically disclosed, this system adopts cold/heat source to measure the equivalent input noise temperature (being noise factor) of measured piece, but, this system noise source used be owing to can only being operated in two fixed temperature states, cannot adopt many temperature spot measurements line number of going forward side by side to improve according to statistics the accuracy of measurement of system with the mode of matching, thereby causes research difficulty large and be difficult for realizing through engineering approaches and apply.Such device is often confined to some high-end quantitative study mechanism and studies.
Because alternating temperature noise source can be exported multiple equivalent output noise temperature values in certain temperature range, therefore such noise source can be carried out the measurement under multiple output noise state of temperature, obtain multiple measurement result value, thereby the method that can adopt least square method or other mathematical statistics and matching is derived final noise-factor measurement result, therefore use alternating temperature measurement of noise source method under guaranteeing compared with the prerequisite of high measurement accuracy, accuracy requirement to noise source itself is relatively easily realized, and is also more convenient for applying.Have and there is the alternating temperature noise source device of tens of K to the variable equivalent output noise temperature of hundreds of K in some research institution's development.Wherein 2009, " national microwave and millimeter wave proceeding " (volume two), the structure that discloses the wide aperture alternating temperature noise source in a kind of 10GHz of being operated in～90GHz frequency range forms.This equipment is made up of wide aperture radiant body, temperature control system, temp measuring system and liquid nitrogen container, and its main application is that the linearity, sensitivity and the stability to being operated in microwave radiometer in 10GHz～90GHz frequency range is calibrated.Owing to having adopted liquid nitrogen cooling in conjunction with electrically heated two PID output control modes with relevant parameter, this device can provide the brightened temperature output of 85K～340K within the scope of 10GHz～90GHz.But the temperature of this noise source adopts liquid nitrogen cooling and electrically heated control mode, cause device alternating temperature mode complexity, the larger alternating temperature speed of wide aperture radiant body volume is slower, and this noise source is exported without coaxial interface, need to connect antenna and carry out wireless radiation output, cannot directly test the low noise amplifier with the wired input of coaxial port.In addition, 2006, " Chinese journal of scientific instrument " the 3rd phase, a kind of low temperature low noise amplifier test macro is disclosed, this system adopts load temperature flexible method, for measuring the noise of low temperature low noise amplifier, but its microwave noise output port and tested amplifier are all put into cooled cryostat, be that noise source and measured piece are all in low temperature environment, can not be applied to the noise factor test of the low noise amplifier with normal temperature input port, and this system is only carried out thermometric to the microwave pad in noise source, the physical temperature of microwave transmission line is not carried out to Real-Time Monitoring, while causing its work, cannot carry out Registration to its equivalent output noise temperature value in real time, thereby can affect its accuracy of measurement.
At present, the document of delivering both at home and abroad, is to use solid-state noise source to measure the method for noise factor substantially, occasionally has document to relate to employing low temperature noise source and the measurement of room noise source, and uses the report of the alternating temperature measurement of noise source with low temperature output port.But pertinent literature and data also do not have normal temperature output port microwave alternating temperature noise source, especially on the microwave pad of noise source and the heat insulation transmission line of microwave and microwave coaxial output port, a series of temperature sensor is installed, can be in the time carrying out surveying work the physical temperature of Real-Time Monitoring microwave pad and the heat insulation transmission line of microwave and microwave coaxial port distribute, and the further record of the equivalent output noise temperature value of Registration microwave coaxial port.
Summary of the invention
Task of the present invention is the weak point existing for above-mentioned prior art, a kind of accuracy of measurement is proposed high, easily apply, can carry out Registration to its equivalent output noise temperature value in real time, be applicable to the microwave alternating temperature noise source of the microwave ultra-low noise amplifier noise-factor measurement with normal temperature coaxle input end mouth.To solve the noise factor difficult parameters of at present numerous microwave ultra-low noise amplifiers and similar products or system with the problem of Measurement accuracy.
Above-mentioned purpose of the present invention can reach by following measures: a kind of normal temperature output port microwave alternating temperature noise source, comprise that upper end is placed in the refrigeration machine 1 of cooled cryostat 4 vacuum environments, be connected to the cold head 2 on refrigeration machine 1 main shaft and be positioned at cold head 2 top radiation the microwave pad 5 that produces thermal noise source, it is characterized in that, on the heat insulation transmission line 6 of microwave radially connecting firmly in microwave pad 5, the temperature sensor 7 of distribution monitoring microwave path physical temperature is installed, the heat insulation transmission line of microwave connects the microwave pad of carrying out alternating temperature in low temperature range to the microwave coaxial output port under normal temperature, temperature sensor 7 linear arrays are arranged by the connected Monitoring and Controlling circuit 3 of temperature monitoring control line, temperature monitoring control circuit 3 arranges instruction according to calibration calculation procedure, the physical temperature of the each link of Real-Time Monitoring microwave path, according to the temperature monitoring numerical value that on the heat insulation transmission line 6 of microwave, temperature sensor 7 feeds back, temperature to refrigeration machine is controlled, by the noise temperature of the microwave pad changing with control variations in temperature in noise source, equivalence exports the microwave coaxial output port 8 under normal temperature to.
The present invention has following technique effect than prior art:
The present invention passes through vacuum pump, by microwave pad, the heat insulation transmission line of series of temperature transducer and microwave is placed in the low temperature environment of sterlin refrigerator and cooled cryostat structure, in the time carrying out surveying work, through temperature monitoring control circuit and microwave coaxial output port, make its physical temperature in normal temperature, and connect the microwave pad of carrying out alternating temperature in low temperature range by the heat insulation transmission line of microwave, pass through microwave pad, series of temperature transducer is all installed on the heat insulation transmission line of microwave and microwave coaxial output port and carries out real-time physical temperature distribution monitoring, with the equivalent output noise temperature value of further Registration microwave coaxial port, solve the noise factor difficult parameters of at present numerous microwave ultra-low noise amplifiers and similar products or system with the problem of Measurement accuracy.
The present invention is provided with a series of temperature sensor 7 on the microwave pad 5 of noise source and the heat insulation transmission line 6 of microwave and microwave coaxial output port 8, can be in the time carrying out surveying work the physical temperature of Real-Time Monitoring microwave pad and the heat insulation transmission line of microwave and microwave coaxial port distribute, and the further equivalent output noise temperature value of Registration microwave coaxial port.
The present invention adopts the heat insulation transmission line of microwave to connect the microwave pad of carrying out alternating temperature in low temperature range to the microwave coaxial output port under normal temperature, make the equivalent output noise temperature of noise source variable within the scope of 50K～200K, and its noise output port in the time carrying out surveying work its physical temperature in normal temperature.Not only reach noise source equivalence output noise temperature variable object in tens of K arrive hundreds of K magnitudes, guaranteed that again this alternating temperature noise source has the ability of the noise factor parameter measurement of the ultra-low noise amplifier that Measurement accuracy input port temperature is normal temperature.Adopt series of temperature transducer to carry out real-time Temperature Distribution monitoring, further guaranteed the accuracy of output port equivalence output noise Temperature Scaling.Overcome low temperature noise source and room noise source building technology difficulty difficult popularization greatly in prior art, or the alternating temperature noise source that output port is low temperature can not be applied to the noise-factor measurement of the low noise amplifier with normal temperature input port and not have Real-Time Monitoring and the shortcoming of calibration noise source equivalence output noise temperature value.And have:
1) be applied to ultra-low noise coefficient and measure, accuracy is high, be easy to promote.The physical temperature of the each link of serviceability temperature transducer Real-Time Monitoring microwave path of the present invention is also calculated and is calibrated to the equivalent output noise temperature of the output port of noise source.Its value quantizes in real time, has guaranteed accuracy and the reliability of noise source output value.Temperature monitoring control circuit carries out reaction type closed-loop control to temperature in Dewar, has guaranteed the stability of noise temperature output.Within the scope of 50K～200K, can export arbitrarily multiple noise temperature values, can utilize the method for mathematical statistics to improve the accuracy in the time of noise-factor measurement, reduce the accuracy requirement of noise source simultaneously, be convenient to through engineering approaches and realize and apply.Solve prior art alternating temperature noise source output port and tested microwave ultra-low noise amplifier all will be under low temperature, can not to have the ultra-low noise amplifier of normal temperature input port carry out noise-factor measurement and cannot Real-Time Monitoring microwave pad and the physical temperature of the heat insulation transmission line of microwave and microwave coaxial port distribute, and the further problem of the equivalent output noise temperature value of Registration microwave coaxial port.
2) alternating temperature noise source output port works in normal temperature, and application is wide.When alternating temperature noise source output port work of the present invention, physical temperature is normal temperature, for measured piece type more extensive, not only can be applied to and adopt the noise figure of amplifier with normal temperature input port of low temperature or superelectron fabrication techniques to measure, also can directly measure on market the widely common normal temperature low noise amplifier of application, also can be applicable to the linearity, the sensitivity of all types of Microwave Low-Noise receivers or microwave radiometer, the calibration fields of measurement of brightness temperature simultaneously.
Accuracy of measurement of the present invention is high, is specially adapted to have the measurement of the ultra-low noise coefficient that approaches the noise factor parameter value limit.
Accompanying drawing explanation
Fig. 1 is the principle schematic of normal temperature output port microwave alternating temperature noise source of the present invention.
Fig. 2 is the embodiment schematic diagram of Fig. 1.
In figure: 1 refrigeration machine, 2 refrigeration machine cold heads, 3 temperature monitoring control circuits, 4 cooled cryostats, 5 microwave pads, the heat insulation transmission line of 6 microwave, 7 temperature sensors, 8 normal temperature microwave coaxial output ports, 9 vacuum pumps, 10 vacuum leads, 11 temperature monitoring control lines, 12 racks.
Embodiment
Consult Fig. 1, Fig. 2.A kind of microwave alternating temperature noise source embodiment for the test of ultralow microwave noise with normal temperature output port describing at Fig. 1, this alternating temperature noise source mainly comprise top under vacuum environment the refrigeration machine 1 in cooled cryostat 4, be connected to radiation on the cold head 2 on refrigeration machine 1 main shaft and produce the microwave pad 5 of thermal noise.Refrigeration machine 1 adopts sterlin refrigerator.The temperature sensor 7 of distribution monitoring microwave path physical temperature is installed on the heat insulation transmission line 6 of the microwave pad 5 of noise source and microwave and microwave coaxial output port 8, temperature sensor 7 linear arrays are arranged on the heat insulation transmission line 6 of microwave, build low temperature environment by refrigeration machine 1 and cooled cryostat 4.Microwave pad 5 is radially fixedly connected with on the heat insulation transmission line 6 of microwave of the outer normal temperature microwave coaxial output port 8 of the connected vacuum tank wall in one end, the heat insulation transmission line 6 of microwave connects the microwave pad of carrying out alternating temperature in low temperature range to the microwave coaxial output port 8 under normal temperature, the temperature sensor 7 of distribution monitoring microwave path physical temperature is installed, microwave pad 5 in noise source is under low temperature, and can in 50K～200K temperature range, carry out alternating temperature, the physical temperature of the microwave coaxial output port 8 of noise source is normal temperature.The cold head 2 connecting firmly on refrigeration machine 1 main shaft is sealed in cooled cryostat 4 together with being arranged in the temperature sensor on the heat insulation transmission line 6 of microwave with linear array, cold head 2 in cooled cryostat 4 is by the connected Monitoring and Controlling circuit 3 of temperature monitoring control line, and the heat insulation transmission line 6 of microwave is radially by cooled cryostat wall and be installed on the normal temperature microwave coaxial output port 8 on rack 12.Vacuum pump 9 is extracted the air in Dewar and transmission line out in real time by vacuum lead 10, makes it in vacuum state, to avoid the inner frosting of Dewar.Noise source each several part is arranged on rack 12.Noise source operation all carries out on temperature monitoring and control circuit 3.Microwave pad 5 radiation on refrigeration machine cold head 2 produce noise temperature and equivalence exports normal temperature microwave coaxial output port 8 to.Temperature monitoring control circuit 3 carries out reaction type closed-loop control to temperature in Dewar, according to calibration calculation procedure, the temperature monitoring numerical value that instruction and series of temperature transducer 7 feed back is set, by temperature monitoring control line 11, the temperature of refrigeration machine is controlled, thereby control the physical temperature of microwave pad 5, the equivalent output noise temperature of microwave pad changes with the variation of the physical temperature of controlling.The heat insulation transmission line 6 of microwave connects microwave pad 5 under low temperature to normal temperature microwave coaxial output port 8.In temperature monitoring control circuit 3, be integrated with the working procedure of whole noise source, and comprise the calibration calculation procedure of noise source equivalence output noise temperature.This calibration calculation procedure is by the microwave transmission line insertion loss value substitution equivalence output noise temperature computation formula of the physical temperature distribution monitoring value on the microwave transmission line of Real-Time Monitoring and accurate detection in advance, and calibration calculation procedure obtains the equivalent output noise temperature exact value of noise source in final normal temperature microwave coaxial output port 8 positions in real time according to equivalent output noise temperature computation formula; In formula, be the equivalent output noise temperature of i+1 section microwave transmission line, unit/K; Be the equivalent output noise temperature of i section microwave transmission line, unit/K; Be the physical temperature arriving of i section microwave transmission line monitoring, unit/K; Be the loss of i section transmission line, unit/dB.
This above-mentioned equivalent output noise temperature value is by the calculating for to ultra-low noise amplifier noise-factor measurement.
Claims (10)
1. a normal temperature output port microwave alternating temperature noise source, comprise that upper end is placed in the refrigeration machine (1) of cooled cryostat (4) vacuum environment, be connected to the cold head (2) on refrigeration machine (1) main shaft and be positioned at cold head (2) top radiation the microwave pad (5) that produces thermal noise source, it is characterized in that, on the heat insulation transmission line of microwave (6) radially connecting firmly in microwave pad (5), the temperature sensor (7) of distribution monitoring microwave path physical temperature is installed, the heat insulation transmission line of microwave (6) connects the microwave pad (5) of carrying out alternating temperature in low temperature range to the microwave coaxial output port (8) under normal temperature, temperature sensor (7) linear array is arranged by the connected Monitoring and Controlling circuit (3) of temperature monitoring control line, temperature monitoring control circuit (3) arranges instruction according to calibration calculation procedure, the physical temperature of the each link of Real-Time Monitoring microwave path, according to the temperature monitoring numerical value of upper temperature sensor (7) feedback of the heat insulation transmission line of microwave (6), temperature to refrigeration machine is controlled, by the noise temperature of the microwave pad changing with control variations in temperature in noise source, equivalence exports the microwave coaxial output port (8) under normal temperature to.
2. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, is characterized in that: the physical temperature of the upper temperature sensor (7) of installing of the microwave pad (5) of noise source and the heat insulation transmission line of microwave (6) real-time distribution monitoring microwave path in measuring process.
3. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, is characterized in that: the normal temperature microwave coaxial output port (8) of noise source is in normal temperature environment, and it is coaxial interface mode.
4. the normal temperature output port microwave alternating temperature noise source as described in claim (1), is characterized in that: noise source operation all carries out on temperature monitoring control circuit (3).
5. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, is characterized in that: temperature monitoring control circuit is integrated with the working procedure of whole noise source in (3), and comprises the calibration calculation procedure of noise source equivalence output noise temperature.
6. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterized in that: calibration calculation procedure is by the microwave transmission line insertion loss value substitution equivalence output noise temperature computation formula of the physical temperature distribution monitoring value on the microwave transmission line of Real-Time Monitoring and accurate detection in advance, in formula, it is the equivalent output noise temperature of i+1 section microwave transmission line, unit/K, be the equivalent output noise temperature of i section microwave transmission line, unit/K; Be the physical temperature arriving of i section microwave transmission line monitoring, unit/K; Be the loss of i section transmission line, unit/dB.
7. normal temperature output port microwave alternating temperature noise source as claimed in claim 6, is characterized in that: calibration calculation procedure obtains the equivalent output noise temperature exact value of noise source in final normal temperature microwave coaxial output port (8) position in real time according to equivalent output noise temperature computation formula.
8. normal temperature output port microwave alternating temperature noise source as claimed in claim 6, is characterized in that: described equivalent output noise temperature value is for the calculating to ultra-low noise amplifier noise-factor measurement.
9. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterized in that: the microwave pad (5) in noise source is under low temperature, and in 50K～200K temperature range, carry out alternating temperature, the physical temperature of the microwave coaxial output port (8) of noise source is normal temperature.
10. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterized in that: the physical temperature of temperature sensor (7) Real-Time Monitoring microwave pad (5) and the heat insulation transmission line of microwave (6) and microwave coaxial output port (8) distributes, determine the equivalent output noise temperature value of mark microwave coaxial port.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107727267A (en) * | 2017-09-28 | 2018-02-23 | 北京无线电计量测试研究所 | A kind of coaxial standard cryogenic noise source |
| CN110231516A (en) * | 2019-06-14 | 2019-09-13 | 北京无线电计量测试研究所 | A kind of quick temperature-changeable microwave noise source |
| CN110411555A (en) * | 2019-07-05 | 2019-11-05 | 北京无线电计量测试研究所 | A kind of high temperature noise source |
| CN113258882A (en) * | 2021-03-31 | 2021-08-13 | 北京无线电计量测试研究所 | System and method for improving equivalent output noise temperature stability |
| CN113589053A (en) * | 2021-08-20 | 2021-11-02 | 中国科学院新疆天文台 | K-waveband radio astronomical refrigeration receiver noise source device |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107727267A (en) * | 2017-09-28 | 2018-02-23 | 北京无线电计量测试研究所 | A kind of coaxial standard cryogenic noise source |
| CN110231516A (en) * | 2019-06-14 | 2019-09-13 | 北京无线电计量测试研究所 | A kind of quick temperature-changeable microwave noise source |
| CN110411555A (en) * | 2019-07-05 | 2019-11-05 | 北京无线电计量测试研究所 | A kind of high temperature noise source |
| CN113258882A (en) * | 2021-03-31 | 2021-08-13 | 北京无线电计量测试研究所 | System and method for improving equivalent output noise temperature stability |
| CN113589053A (en) * | 2021-08-20 | 2021-11-02 | 中国科学院新疆天文台 | K-waveband radio astronomical refrigeration receiver noise source device |
| CN113589053B (en) * | 2021-08-20 | 2023-04-25 | 中国科学院新疆天文台 | K wave band radio astronomical refrigeration receiver noise source device |
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